Fluid fuel burner assembly



March 14, 1961 R. E. SEELY FLUID FUEL BURNER ASSEMBLY Filed Oct. 31, 1956 United StatesPatent O FLUID FUEL BURNER ASSEMBLY Richard E. Seely, Fort Wayne, Ind., assignor to General Electric Company, a corporation of New York Filed Oct. 31, 1956, Ser. No. 619,590

Claims. (Cl. 230-117) This invention relates to fluid fuel burner assemblies, andmore particularly to an improved assembly incorporating an electric motor structure.

In furnaces which utilize a fluid fuel, such as oil, it is customary to provide a blower and an electric motor in operative relation therewith in order to furnish the air necessary for proper combustion of the fuel as it is forced into the furnace chamber. Since such furnaces are used in large numbers in residences, it is imperative that there be no chance at all of injury or damage resulting from faulty operation of the electric motor. In particular, it is important that if any part of the electric motor catch on fire, it should not be possible for any burning particles to enter the room in which the furnace is located. The method thus far used to insure that no such thing can happen has been to make the motor totally enclosed with the shaft extending through a seal at one end thereof so as to be drivingly connected to.the blower. The fact .that the motor has been totally enclosed has provided a rather acute cooling problem; in order to effect the necessary cooling of the motor, it has been necessary to increase the amount of copper and iron in the motor so as to dissipate the heat more effectively. While this achieves the purpose, the cost of the additional material, and the fact that it is not necessary for operating purposes, makes the solution somewhat undesirable despite its necessity.

It is, therefore, an object of this invention to furnish a fluid-fuel burner assembly including a blower and an electric motor for operating the same wherein the two are related in such a way as to eliminate the need for the increased amount of material in the motor which has been present primarily for cooling purposes.

A further object of this invention is to provide an electric motor having a housing so formed as to cooperate with the remainder of the assembly in a novel manner to effect the decrease in the amount of material used while retaining the necessary cooling effect on the motor.

In one aspect the invention provides, in a fluid fuel burner assembly, a radial type fan which has a radially extending disc with a plurality of blades extending therefrom On one side thereof. An electric motor is positioned on the other side of the disc in driving relation therewith, and a housing is positioned about the fan and the motor so as to form communicating motor and fan cavities with one end of the motor cavity being defined by the disc. The housing further forms an air outlet passage in communication with the peripheral surface of the fan blades, and at least one inlet opening on that side of the fan which is remote from the motor. The housing is con structed so as to totally enclose the fan and the motor except for the foresaid inlet and outlet provisions. In this manner, one end of the motor cavity is formed by a disc which, during operation of the motor, rotates rapidly and has a high air flow on its other side; by this means, the disc can remove heat from the motor in a highly effective manner. In addition, there is of course a clearance around the ends of the disc through which some Patented Mar. 14, 19 61 air will flow between the fan cavity and the motor cavity further to increase the amount of cooling efiected on the motor.

This construction is in contrast to that presently used whereby the motor is totally enclosed not only as to the surrounding room but also as to the blower apparatus, that is, the motor is completely enclosed within its own solid housing with only its shaft extending through a seal so as to operate the blower. The present invention on the other hand contemplates a motor Where the housing includes a solid housing shell positioned about the stator and the rotor, a solid end flange joined to the shell at one end of the stator and rotor and arranged rotatably to support the shaft,-and a second end flange which performs the same function for the shaft position at the other end of the stator and rotor. The second end flange has a substantial portion of its surface formed into openings extending therethrough so that when it is assembled into operative relationship with the blower there will be substantial communication between the motor cavity and the fan cavity.

The features of the invention which are believed to be novel are set forth with particularity in the appended claims. The invention, itself, however, both as to its organization and method of operation together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawing.

In the drawing, Figure 1 is a side view of a fluid fuel furnace of the type in which the improved construction of the invention is incorporated;

Figure 2 is a side view, partly broken away and partly in cross section of the improved assembly of this invention;

Figure 3 is a view along line 33 in Figure 2;

Figure 4 is a view of the fan disc described in connection with Figure 2; and

Figure 5 is a view of a modified fan disc which may be used in the assembly of the invention.

Referring now to Figures 1 to 4 of the drawing, there is shown a furnace 1 of the type which utilizes a fluid fuel, together with an assembly 2 having a portion 3 extending into the furnace 1 for injecting the fluid fuel and a suitable amount of combustion air into the furnace. Referring particularly to Figure 2, assembly 2 includes a motor assembly 4, a blower assembly 5, a pumping assembly 6 and a fuel gun assembly 7 which is contained within part 3.

The motor assembly 4 includes a stator 8 having a main winding 9 and a starting winding 10 positioned thereon; concentrically positioned within the stator 8 is a rotor 11 which imparts its rotation to a shaft 12 on which is positioned a centrifugal mechanism 13. As is well known in the art, the motor is connected across a source of single phase alternating current power with its windings in parallel with each other; after it has substantially come up to running speed, the starting winding 10 is disconnected by the centrifugal mechanism 13 so that the motor continues to run on the main Winding Q alone. It will be understood that the details of the motor structure have been described for illustrative purposes only and that other types of motors may be provided.

Stator 8 is secured within an imperforate cylindrical housing portion, or shell 14 having end flanges 15 and 16 secured thereto. End flange or shield 15 is a substantially imperforate part in the same manner as shell 14 which coacts therewith to cover the outer surface of stator 8 and one end of stator 8 and rotor 11; however, end shield 16, which may be seen to advantage in Figure 3, has a substantial portion of its surface formed into openings 17 extending therethrough, and is further as to form a blower wheel.

provided with an annular rabbet surface '18. End shields i and 16 are provided with bearings 19 and 20 respectively to provide support for shaft 12 at each end of stator 8 and rotorllJ Housing shell 14 and end shield 15 form the sides of the motor enclosures; end shield 16 on the other hand is provided only for support of shaft 12 and for attachment to the remainder of the assembly as will be described herebelow; it is provided with sufiicient openings so that it is not to be considered in itself as a termination of the cavity 21 in which the motor parts are positioned.

At the right end of shaft 12 beyond end shield 16 a disc member 22 of good heat conductive material (such as metal) is secured to the shaft. The side of disc 22 which is toward motor assembly 4 is preferably formed so as to provide radially extending projections 27 for -a is left substantially open so as to be in communication -with the fan assembly cavity when the motor is assempurpose which will be explained herebelow. A plural- -ity of fan blades 23 are in turn secured to the disc 22 adjacent its outer periphery, extending from the disc on the opposite side thereof from the motor assembly 4 so The blower wheel, or fan assembly, is contained in a housing 24 which includes a portion 25 having air inlets 26; housing 24 merges into housing portion 3 which forms an outlet passage in communication with the peripheral surface of fan blades 23 for discharging air sucked in by the blower from the inlets 26. The blower wheel thus forces air through passage 3 into the furnace 1. Housing member 24 also ment with rabbet 18 of end flange 16.

As illustrated in Figure 2, assembly 2 also includes a fuel pumping assembly 6 which forces the fuel through a pipe 28 and out through the end 29 of the pipe 28 which is formed to'act as a fuel gun. Suitable electrical apparatus 30 may be provided to cause a spark to pass between the two ends of conductors 31 and thus ignite the fuel as it leaves gun 29 and passes into the furnace 1. However, it is to be understood that the invention in this case relates primarily to the blower and motor assemblies and the combination thereof in a predetermined relationship, and that the pumping and igniting apparatus has been shown merely to illustrate the invention in its normal environment.

It will now be seen that housing 24 forms a blower cavity 25 and completely encloses the blower with the exception of the outlet passage 3 and the inlet openings or passages 26. It will further be seen that both the outlet passage and the inlet openings 26 are on the other side of disc 22 from the motor assembly 4. motor cavity 21 is terminated at the right end thereof by the disc 22 which forms a part of the fan assembly, and projections 27 on the disc act as small fan blades to stir up the air in the motor cavity and thus cause a continual flow of air over the motor. In addition, the thin disc 22 will serve to conduct heat from the motor through the disc itself so that the heat is carried off by the flow of air which passes across the other side of the disc 22. Thus, the disc performs a dual cooling function; it stirs the air through its rotation; and it removes heat from the air in the motor cavity by conduction through the rotating disc. In addition, there is, of course, a clearance 36 between the casing 24 and the outer edge or peripheral surface of disc 22, and this will cause a small interchange of the blower air with the air in the motor which is not sufficient to lower the blower output noticeably but does have some cooling effect.

It will be seen from the foregoing that this invention provides an assembly wherein a blower and the motor for operating the blower are so arranged that the motor benefits substantially from the cooling effect of the blower and thus may be made more efficiently with less material to effect the same purpose. It will further be seen 'that the invention provides, as a subcombination, an improved motor construction in which the motor is entire- 'ly enclosed in its housing except at one end thereof which In effect,

.includes a flange portion 32 which extends into engage- 1 bled in the combination.

Referring now to Figure 5, there is shown a modified form of the fan disc which may be used instead of the disc 22 described in connection with Figures 1 to 4. In this case, the modified disc 33 has projections 34 similar to projections 27 of disc 22 to effect the same air moving purpose. In addition, however, several relatively small openings 35 are provided substantially radially inward from the periphery of the disc; openings 35 form an added communication between the motor cavity 21 and the fan cavity 25. Air enters the motor cavity in the manner set forth above for the first embodiment of disc22 and passes out from the motor cavity 21, both through openings 35 and clearance 36 of the casing and the outer edge of the disc 33 without substantially affecting the performance of the blower, thus augmenting the cooling effect on the motor. This modification of the disc is provided to illustrate the point that" the particular construction of the disc may be varied as the cooling needs of the motor dictate.

While the invention has been explained by describing a particular embodiment thereof, it will be apparent that improvements and modifications may be made without departing from the scope of the invention as defined in the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a fluid fuel burner, a housing forming a motor cavity andv a fan cavity with an opening formed therebetween, an electric motor mounted in said motor cavity, said motor comprising a stator and rotor, a fan arranged in said fan cavity for feeding fluid to a fuel burner, means connecting said rotor to drive said fan,

said fan including a radially extending disc of heat conducting material positioned adjacent said opening to define one end of said motor cavity and a plurality of fluid moving blades located adjacent the side of said disc remote from said motor cavity, said disc having at least one radially extending projection formed on its side facing said motor, said fan cavity having at least one fluid outlet passage in communication with the periphery of said blades and leading to the fuel burner and further having at least one fluid inlet passage, and said housing totally enclosing said motor and said fan except for said inlet and outlet passages with said disc being in free communication with said motor for transferring heat away from said motor and said motor cavity to cool said motor during operation thereof.

2. In a fluid fuel burner; an electric motor comprising a stator and a rotor; a motor housing including an imperforate shell portion surrounding said stator, a first end flange having a substantial portion of its surface formed into openings extending therethrough joined to said shell portion at one end of said stator, and an imperforate second end flange joined to said shell portion at the otherend of said stator; means carried by said first and second end flanges for rotatably supporting said rotor; a fan housing mounted adjacent said first end flange and formed with a Wall defining an opening communicating with the interior of said motor housing and said motor; a radial type fan arranged to rotate in said fan housing; driving connection means between said fan and said rotor; said fan including a radially extending disc of heat conducting material disposed adjacent said opening and in free communication with said motor for transferring heat from said motor housing to said fan housing to cool said motor during operation thereof, said disc substantially closing said opening to form one end of said motor housing but having its peripheral surface spaced from said fan housing wall to provide fluid circulation between said motor housing and said fan housing, circumferentially spaced fan blades extending from the side of said disc remote from said motor housing, said fan housing having at least one fluid outlet passage in communication with the periphery of said fan blades and further having at least one fluid inlet passage; said motor being totally enclosed within said motor housing except for the space at the periphery of said disc and being cooled by heat transfer through said disc and by the fluid circulation through said space.

3. In a fluid fuel burner, an electric motor comprising a stator and a rotor, a motor housing including an imperforate shell portion surrounding said stator, a first end flange having a substantial portion of its surface formed into openings extending therethrough joined to said shell portion at one end of said stator, and an imperforate second end flange joined to said shell portion at the other end of said stator, means carried by said first and second end flanges for rotatably supporting said rotor, a fan housing secured to said first end flange and formed with a wall defining an opening cornmunicating with the interior of said motor housing; driving connection means between said fan and said rotor; a radial type fan arranged to rotate in said fan housing; said fan including a radially extending disc of heat con ducting material disposed adjacent said opening and in free communication with said motor for transferring heat from said motor housing to said fan housing to cool said motor during operation thereof, said disc substantially closing said opening to form one end of said motor housing but having its peripheral surface spaced from said fan housing wall to provide fluid circulation between said motor housing and said fan housing, said disc having at least one radially extending projection formed on its side facing said motor, circumferentially spaced fan blades extending from the side of said disc remote from said motor housing, said fan housing having at least one fluid outlet passage in communication with the periphery of said fan blades and further having at least one fluid inlet passage; said motor being totally enclosed within said motor housing except for the space at the periphery of said disc and being cooled by heat transfer through said disc and by the fluid circulation through said space.

4. In a fluid fuel burner, a housing forming a motor cavity and a fan cavity with an opening formed therebetween, an electric motor mounted in said motor cavity, said motor comprising a stator and a rotor, a fan arranged in said fan cavity for feeding fluid to a fuel burner, means connecting said rotor to drive said fan, said fan including a radially extending disc of heat conducting material positioned adjacent said opening to define one end of said motor cavity and a plurality of fluid moving blades located adjacent the side of said disc remote from said motor cavity, said disc having at least one radially extending projection formed on its side facing said motor and having a plurality of openings formed therein substantially inwardly from the periphery thereof, said fan cavity having at least one fluid outlet passage in communication with the periphery of said blades and leading to the fuel burner and further having at least one fluid inlet passage, and said housing totally enclosing said motor and said fan except for said inlet and outlet passages with said disc being in free communication with said motor for transferring heat from said motor cavity to cool said motor during operation thereof.

5. In a fluid fuel burner; an electric motor comprising a stator and a rotor; a motor housing including an imperforate shell portion surrounding said stator, 21 first end flange having a substantial portion of its surface formed into openings extending therethrough joined to said shell portion at one end of said stator, and an imperforate second end flange joined to said shell portion at the other end of said stator; means carried by said first and second end flanges for rotatably supporting said rotor; a fan housing secured to said first end flange and formed with a wall defining an opening communicating with the interior of said motor housing; driving connection means between said fan and said rotor; a radial type fan arranged to rotate in said fan housing; said fan including a radially extending disc of heat conducting material disposed adjacent said opening and in free communication with said motor for transferring heat from said motor housing to said fan housing to cool said motor during operation thereof, said disc substantially closing said opening to form one end of said motor housing but having its peripheral surface spaced from said fan housing Wall to provide fluid circulation between said motor housing and said fan housing, said disc having at least one radially extending projection formed on its side facing said motor and having a plurality of openings formed therein substantially inwardly from said peripheral surface, circumferentially spaced fan blades extending from the side of said disc remote from said motor housing; said fan housing having at least one fluid outlet passage in communication with the periphery of said fan blades and further having at least one fluid inlet passage; said motor being totally enclosed Within said motor housing except for the space at the periphery of said disc and said disc openings and being cooled by heat transfer through said disc and by the fluid circulation through said disc openings and said space.

References Cited in the file of this patent UNITED STATES PATENTS 1,733,499 Klemm Oct. 29, 1929 2,207,317 Gear July 9, 1940 2,260,042 McMahan Oct. 21, 1941 2,360,924 Wolfert et al Oct. 24, 1944 2,517,233 Peters Aug. 1, 1950 2,611,322 Wahle Sept. 23, 1952 FOREIGN PATENTS 835,117 Germany Mar. 27, 1952 977,956 France Nov. 22, 1950 1,022,687 France Dec. 17, 1952 

